Stringed instruments such as a guitar include a body and a neck, which extends from the body. A set of strings is stretched across the body and longitudinally along over the neck. Each string terminates at a contact point on a bridge, and stretches the length of the neck terminating at a nut at the end of the neck where it meets the headstock. The point at which the string contacts the bridge and the point at which the string contacts the nut define a string length over which the string vibrates. The length of the string, along with the string tension define the pitch produced by the string's vibration.
The neck of the instrument may have frets disposed on its surface defining raised lines that are generally parallel to the nut (i.e. transverse to the longitudinal axis of the neck). A player presses down on the strings until the string contacts one of the frets. When the string contacts the fret, it defines a new string length between the bridge and the fret which is shorter than the distance between the bridge and the nut. Plucking or strumming the string will produce a pitch higher than the pitch of the open string, and the player can thereby control the notes created from the instrument.
Other properties relating to pitch may be manipulated by the player by controlling the length and tension of the strings. For example, bending is a fingering technique whereby a player presses down on a string at a given fret and then pushes up or down transverse to the neck (e.g. bends the string) to increase the tension on the string at the fret. This produces a higher pitch sound than the sound of an undeformed string at the same fret. By bending strings, the player can transition from the base note to a higher note in a gradual manner without having to pluck or strum the second note. While bending can create a higher pitched note, there is not a way of manipulating strings at the frets to produce a lower pitch. Lowering the pitch requires lengthening the string or reducing the tension of the string, which cannot be performed by the player on the fret board through fingering techniques.
To produce an effect of lower pitch, tremolo devices have been developed which modify or move the bridge of the instrument to allow the player to control the tension of the string to a limited degree. By moving the bridge such that the termination point of the string at the bridge moves closer to the neck, the tension of the string is reduced and the pitch of the resultant note is lowered. Thus, the tremolo device produces a vibrato effect, allowing the player to oscillate through varying frequencies and producing a varying pitch within a sustained note. Traditional tremolo devices incorporate a plate which holds the bridge device. The plate typically has an edge which serves as a pivot fulcrum. A lever handle is attached to the plate, allowing the player to move the handle to pivot the plate along its fulcrum edge. The pivoting of the plate moves the bridge closer to or further from the neck to vary the tension of the strings. Other tremolo devices use cylindrical cams at the bridge over which the strings are stretched. The cam is rotated to vary the point where the string makes contact with the cam to adjust the length and tension of the string. Conventional tremolo devices may require openings or routing paths in the guitar body to allow the bridge mechanism to pivot and to provide counterbalancing springs to bring the tremolo device back to its original undeployed position.
One well-known problem with tremolo devices is that once the tremolo device is deployed, the string does not return to the exact pitch that it had prior to using the tremolo device (e.g. the string is out of tune). Accordingly, a player may tune the instrument to bring the set of strings into tune, and begin playing. While playing, the player deploys the tremolo device that moves the bridge to increase or reduce the tension on one or more of the strings. This causes the string to slide at the contact points at the bridge and/or the nut. Seldom does the string return to the exact seated position that it held prior to using the tremolo and therefore, the string falls out of tune. In addition, each string in a set of strings has a different gauge or diameter. When the tremolo device moves the bridge, it applies an equal force or movement to all strings in the set. Because of their different sizes, the force affects each string slightly differently, which may cause the strings to fall slightly out of tune relative to one another.
Alternative structures and techniques are desired.